The vibration-damping alloys which absorb the vibration transmitted from an external source and reduce it rapidly have been studied for practical application in various fields of industry for the purpose of, for example, preventing any noise from being generated by the transmission of vibration.
The vibration-damping alloys are classified by their vibration-damping mechanism into four types as listed below:
(1) Soft ferromagnetic alloy;
(2) Thermoelastic martensite alloy;
(3) Al--Zn alloy; and
(4) Alloy relying upon a pseudo-elastic behavior.
The alloy as mentioned at (1) has the drawback of being incapable of damping vibration in the presence of an internal stress, and having, therefore, only a limited scope of applicability. The alloy as mentioned at (2) is too low in workability, and expensive for practical use. The alloy as mentioned at (3) is too low in strength to be sufficiently durable as a structural material.
The alloy as mentioned at (4) has been developed as a material not having any of the drawbacks as pointed out above. A vibration-damping alloy which relies upon the pseudo-elastic behavior of a stacking fault has been proposed in Japanese Patent Application Laid-Open No. 162746/1989. It discloses by way of example Fe--Ni--Mn Fe--Ni--Cr alloys having an austenitic structure, and a nickel content of 10 to 30%.
The above Japanese Application shows Fe--Ni--Mn Fe--Ni--Cr alloys as examples of the vibration-damping alloys. The strength of these alloys is, however, only as high as that of SUS304 stainless steel, and it is, therefore, desirable to improve their strength without lowering their vibration-damping properties.
This invention is a vibration-damping alloy intended as a solution to the above problems for improving the strength of one of the above alloys without lowering its vibration-damping properties, by adding to it a small amount of one or more elements selected from elements contributing to its solid-solution hardening, such as Si and P, and elements contributing to its precipitation hardening, such as Cu, Al, Mo, Ti, Nb, Be, N and B. It is an object of this invention to provide a novel vibration-damping alloy of relatively high strength which relies upon the movement of a twin and the pseudo-elastic behavior of a stacking fault, is excellent in strength, workability and weldability, is inexpensive, and is, therefore, suitable for use in making a variety of structural members or materials.